Loudspeakers have two primary specifications: (1) the frequency response pointed in the direction of the listener and (2) the ratio of sound launched towards the listener vs. elsewhere within the room. The first specification is known as the listening window response of the loudspeaker and the second specification is the directivity index of the loudspeaker. While a great deal of attention has traditionally been paid to the frequency response, less attention has been paid to the directivity of a loudspeaker.